I have the Essence STX with OpAmp Mod for 1.5 Years, and therefor compared to the Xonar DG i can say even with the cheepo Koss Porta Pro the DG sounds Crap for my Ears,
tested with the same FLAC Files and Headphones (HD 650 also). Well, it was only for sometimes listening to the Music when i am working with PS, so i can enjoy my tunes,
therefor i won't buy a 2nd Essence STX, but the Sound Quality is bad compared to the STX, the DG is Asus cheapest Xonar Card. But what really goes on my nerves, no Add On
Soundcard made ever this: When i am using Photoshop Plugins that require a bit Processing Time, the Sound really stutters, stops for some seconds or more...so it's basically
really Crap for me...even my old 2006 bought Creative X-Fi Extreme Music never did this....the STX is built into my Linux Box, which is my main PC for Ages, still yet running
Ubuntu 11.04....